The Chicago Cubs and Boston Red Sox are finalizing a deal that would make Theo Epstein the Cubs' president of baseball operations, according to a baseball source.

The source said it could happen Thursday, but as of early Friday morning, the deal was not done.

A source with knowledge of the negotiations said: "The two sides are on the 5-yard line." Major League Baseball already has told the Cubs that they can have a news conference Friday to introduce Epstein, according to a source with knowledge of the situation.

Sources confirmed to ESPNChicago.com and ESPNBoston.com that San Diego Padres general manager Jed Hoyer will be named Cubs GM a few days after Epstein's news conference.

Hoyer will be granted permission to leave when San Diego promotes senior vice president of baseball operations Josh Byrnes to vice president/GM, a source said. Byrnes was GM of the Arizona Diamondbacks when Padres owner Jeff Moorad was part-owner of that team. Sources said Moorad has wanted Byrnes to return to the job, even though he respected Hoyer, whom he hired in 2010.

The Red Sox aimed high in asking for compensation for Epstein. A baseball source told ESPNBoston.com that they initially asked for the Cubs young star shortstop Starlin Castro. Whey they were rebuffed, the Red Sox asked for arguably the Cubs best starting pitcher in Matt Garza.

A major league source told ESPNChicago.com that at one point Boston proposed that the Cubs take pitcher John Lackey's contract. Lackey has three seasons remaining on a five-year, $82.5 million contract. He was 12-12 with a 6.41 ERA in 28 starts for the Red Sox in 2011.

But the expected agreement will include Cubs minor leaguers, although not top prospects Brett Jackson, Trey McNutt or Matt Szczur, the source said. Cash will not be part of the compensation.

The Red Sox would not confirm a deal is imminent. In fact, owner John Henry told the Boston Globe that a deal is "not close." Still, an official with one of the teams involved suggested it was possible an agreement has been reached, but that it would be unlikely for either the Cubs or Red Sox to make an announcement before the Red Sox review the medical records of the player or players they will receive.

If compensation talks can't be pushed over the goal line, baseball commissioner Bud Selig told Sirius XM that he may have to step in to help mediate the impasse.

"It's a possibility," Selig said on the radio. "No question, it is a possibility."

A source told ESPNBoston.com that Epstein originally asked Byrnes to join him in Chicago, but Byrnes declined. Epstein then turned to Hoyer, his longtime friend and former assistant. Hoyer went to Moorad, told him of the offer from Epstein and said he would stay if the Padres gave him a five-year extension. Moorad, though reluctant to lose Hoyer, the source said, said he would not grant him the extension and told him he was free to take the Cubs job.

In an email to ESPNBoston.com late Wednesday night, though, Moorad said that the Cubs had not asked for official permission to interview Hoyer.

In another Cubs staffing development, ESPNBoston.com has confirmed that Padres assistant GM Jason McLeod will also join Epstein and Hoyer in Chicago.

There will be no compensation for Hoyer, a source told ESPNChicago.com and ESPNBoston.com. Moorad and Cubs chairman Tom Ricketts have become friends since the Ricketts family bought the Cubs in October 2009. Ricketts was in San Diego on Sept. 28, the last day of the regular season, and did not return with the Cubs on the flight back to Chicago. Ricketts met with Moorad and sat with him, Byrnes and Hoyer during the season finale.

Byrnes and Hoyer worked with Epstein in Boston before leaving for their new jobs. Hoyer took over as Padres GM in 2010 after Kevin Towers was fired. McLeod worked for the Red Sox in the scouting department for seven years before going to the Padres. One remaining piece missing from Epstein's original team of key advisors is Red Sox special assistant Dave Finley, who could also possibly be in play for Epstein in Chicago.

Bruce Levine covers baseball for ESPNChicago.com and ESPN 1000. Information from ESPNBoston.com's Gordon Edes was used in this report.